l2tp: don't set sk_user_data in tunnel socket

l2tp no longer uses the tunnel socket's sk_user_data so drop the code
which sets it.

In l2tp_validate_socket use l2tp_sk_to_tunnel to check whether a given
socket is already attached to an l2tp tunnel since we can no longer
use non-null sk_user_data to indicate this.

Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index c97cd0fd851482004cba7c91e7c82127a84110ba..59a171fa1a39a9311f34a636bd3e519ee09d680c 100644 (file)
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -1263,7 +1263,6 @@ static void l2tp_tunnel_destruct(struct sock *sk)
        /* Remove hooks into tunnel socket */
        write_lock_bh(&sk->sk_callback_lock);
        sk->sk_destruct = tunnel->old_sk_destruct;
-       sk->sk_user_data = NULL;
        write_unlock_bh(&sk->sk_callback_lock);
 
        /* Call the original destructor */
@@ -1554,6 +1553,8 @@ EXPORT_SYMBOL_GPL(l2tp_tunnel_create);
 static int l2tp_validate_socket(const struct sock *sk, const struct net *net,
                                enum l2tp_encap_type encap)
 {
+       struct l2tp_tunnel *tunnel;
+
        if (!net_eq(sock_net(sk), net))
                return -EINVAL;
 
@@ -1567,8 +1568,11 @@ static int l2tp_validate_socket(const struct sock *sk, const struct net *net,
            (encap == L2TP_ENCAPTYPE_IP && sk->sk_protocol != IPPROTO_L2TP))
                return -EPROTONOSUPPORT;
 
-       if (sk->sk_user_data)
+       tunnel = l2tp_sk_to_tunnel(sk);
+       if (tunnel) {
+               l2tp_tunnel_dec_refcount(tunnel);
                return -EBUSY;
+       }
 
        return 0;
 }
@@ -1607,12 +1611,10 @@ int l2tp_tunnel_register(struct l2tp_tunnel *tunnel, struct net *net,
        ret = l2tp_validate_socket(sk, net, tunnel->encap);
        if (ret < 0)
                goto err_inval_sock;
-       rcu_assign_sk_user_data(sk, tunnel);
        write_unlock_bh(&sk->sk_callback_lock);
 
        if (tunnel->encap == L2TP_ENCAPTYPE_UDP) {
                struct udp_tunnel_sock_cfg udp_cfg = {
-                       .sk_user_data = tunnel,
                        .encap_type = UDP_ENCAP_L2TPINUDP,
                        .encap_rcv = l2tp_udp_encap_recv,
                        .encap_err_rcv = l2tp_udp_encap_err_recv,